U.S. patent application number 16/526764 was filed with the patent office on 2021-02-04 for bubble detector on proximal end of catheter with fail-safe mechanism.
The applicant listed for this patent is Biosense Webster (Israel) Ltd.. Invention is credited to Yehuda Algawi, Andres Claudio Altmann, Christopher Thomas Beeckler, Assaf Govari.
Application Number | 20210030465 16/526764 |
Document ID | / |
Family ID | 1000004270911 |
Filed Date | 2021-02-04 |
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United States Patent
Application |
20210030465 |
Kind Code |
A1 |
Algawi; Yehuda ; et
al. |
February 4, 2021 |
Bubble Detector on Proximal End of Catheter with Fail-Safe
Mechanism
Abstract
A system includes a probe, a processor, and a bubble detector.
The probe is configured for insertion into a lumen of a patient and
is coupled to an irrigation pump. The processor is configured to
control delivery of irrigation fluid to the probe by turning on and
controlling the irrigation pump. The bubble detector is coupled to
a proximal portion of the probe. In response to the irrigation pump
being turned on, the bubble detector is configured to automatically
start detection of gas bubbles in the irrigated fluid, and transmit
fail-safe signals indicating fail-safe bubble detection is
operational. The processor is further configured to monitor the
fail-safe signals and, in absence of fail-safe signals, to
automatically disable delivery of the irrigation fluid.
Inventors: |
Algawi; Yehuda; (Binyamina,
IL) ; Govari; Assaf; (Haifa, IL) ; Altmann;
Andres Claudio; (Haifa, IL) ; Beeckler; Christopher
Thomas; (Brea, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Biosense Webster (Israel) Ltd. |
Yokneam |
|
IL |
|
|
Family ID: |
1000004270911 |
Appl. No.: |
16/526764 |
Filed: |
July 30, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 2291/02433
20130101; A61M 1/0058 20130101; A61M 5/365 20130101; A61B 2217/005
20130101; A61B 2018/00011 20130101; A61B 2218/002 20130101; A61B
2018/00744 20130101; A61B 2017/003 20130101; A61B 2018/00577
20130101; A61M 2209/02 20130101; A61B 2217/007 20130101; A61B
18/1492 20130101; A61B 17/00234 20130101 |
International
Class: |
A61B 18/14 20060101
A61B018/14; A61B 17/00 20060101 A61B017/00; A61M 1/00 20060101
A61M001/00; A61M 5/36 20060101 A61M005/36 |
Claims
1. A system, comprising: a probe for insertion into a lumen of a
patient, wherein the probe is coupled to an irrigation pump; a
bubble detection sub-system disposed proximate an outlet of the
irrigation pump; a processor, which is configured to control
delivery of irrigation fluid to the probe by turning on and
controlling the irrigation pump; a bubble detector coupled to a
proximal portion of the probe, wherein, in response to the
irrigation pump being turned on, the bubble detector is configured
to: automatically start detection of gas bubbles in the irrigated
fluid; and transmit fail-safe signals indicating fail-safe bubble
detection is operational; and wherein the processor is further
configured to monitor the fail-safe signals and, in absence of
fail-safe signals, to automatically disable delivery of the
irrigation fluid.
2. A system, comprising: a probe for insertion into a lumen of a
patient, wherein the probe is coupled to an irrigation pump; a
processor, which is configured to control delivery of irrigation
fluid to the probe by turning on and controlling the irrigation
pump; a bubble detector coupled to a proximal portion of the probe,
wherein, in response to the irrigation pump being turned on, the
bubble detector is configured to: automatically start detection of
gas bubbles in the irrigated fluid; and transmit signals indicating
bubble detection is operational; and wherein the processor is
further configured to monitor the signals and, in absence of
signals, to automatically disable delivery of the irrigation
fluid.
3. The system according to claim 2, further comprising a bubble
detection system disposed proximate an outlet of the irrigation
pump.
4. The system according to claim 1, wherein the processor is
further configured to alert a user that the delivery of the
irrigation fluid is disabled.
5. The system according to claim 1, wherein the bubble detector is
configured to transmit the fail-safe signals every prespecified
time interval.
6. The system according to claim 1, wherein the processor is
further configured to present to a user an option to override, for
a given time duration, the automatic disabling of the delivery of
the irrigation fluid.
7. The system according to claim 1, wherein the bubble detector is
electrically wired to power leads of the irrigation pump, and is
thus configured to start the detection in response to the
irrigation pump being turned on.
8. The system according to claim 1, wherein the bubble detector is
wired in parallel to an auxiliary power source that retains the
bubble detector in a ready mode, so as to start operating within a
given time delay after the irrigation pump is turned on.
9. The system according to claim 1, wherein the bubble detector is
wired in parallel to an auxiliary power source that powers the
bubble detector regardless of whether the irrigation pump is turned
on or off.
10. The system according to claim 1, and comprising a drip
detector, which is attached to a drip chamber of a saline bag that
contains saline for use during purge, wherein the drip detector is
configured to send to the irrigation pump an indication that saline
is dripping out of the bag, and wherein if no indication is sent, a
pump logic is configured to disable a purge button.
11. The system according to claim 10, wherein the pump logic is
further configured, if no indication is sent from the drip
detector, and an indication of decreasing level of saline in the
drip chamber is received from a level indicator attached to a drip
chamber, to terminate any ablation currently occurring and reduce
the flow rate to an idle flow.
12. A method, comprising: inserting a probe into a lumen of a
patient, wherein the probe is coupled to an irrigation pump;
controlling delivery of irrigation fluid to the probe by turning on
and controlling the irrigation pump; in response to the irrigation
pump being turned on, controlling a bubble detector coupled to a
proximal portion of the probe to automatically start detection of
gas bubbles in the irrigated fluid, and to transmit fail-safe
signals indicating fail-safe bubble detection is operational; and
monitoring the fail-safe signals and, in absence of fail-safe
signals, automatically disabling delivery of the irrigation
fluid.
13. The method according to claim 12, and comprising alerting a
user that the delivery of the irrigation fluid is disabled.
14. The method according to claim 12, wherein transmitting the
fail-safe signals comprises transmitting the fail-safe signals
every prespecified time interval.
15. The method according to claim 12, and comprising presenting to
a user an option to override, for a given time duration, the
automatic disabling of the delivery of the irrigation fluid.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to invasive
procedures, and specifically to monitoring of irrigation fluid used
during invasive procedures.
BACKGROUND OF THE INVENTION
[0002] During some invasive medical procedures, tissue may be
irrigated, and the irrigation fluid used may be monitored for the
occurrence of bubbles. A number of bubble monitoring techniques
were previously proposed in the patent literature. For example,
EP0053453, EP3076137, CN109789269 each describes a bubble detection
system. U.S. Patent Application Publication 2019/054256 describes a
method, including ejecting irrigation fluid from a distal end of a
probe so as to irrigate tissue, and receiving, over a period of
time, initial signals indicative of respective temperatures of the
distal end, from a temperature sensor in the distal end. The method
also includes formulating from the initial signals a temperature
range between upper and lower temperature thresholds and, when a
further signal from the temperature sensor, received subsequent to
the period of time, is indicative of a further temperature above
the upper temperature threshold, raising an alarm that a bubble is
present in the irrigation fluid. All of the documents referenced
are hereby incorporated by reference as if set forth herein with a
copy in the Appendix.
SUMMARY OF THE INVENTION
[0003] An embodiment of the present invention provides a medical
system including a probe, a processor, and a bubble detector. The
probe is configured for insertion into a lumen of a patient and is
coupled to an irrigation pump. The processor is configured to
control delivery of irrigation fluid to the probe by turning on and
controlling the irrigation pump. The bubble detector is coupled to
a proximal portion of the probe. In response to the irrigation pump
being turned on, the bubble detector is configured to automatically
start detection of gas bubbles in the irrigated fluid, and transmit
fail-safe signals indicating fail-safe bubble detection is
operational. The processor is further configured to monitor the
fail-safe signals and, in absence of fail-safe signals, to
automatically disable delivery of the irrigation fluid.
[0004] In some embodiments, the processor is further configured to
alert a user that the delivery of the irrigation fluid is
disabled.
[0005] In some embodiments, the bubble detector is configured to
transmit the fail-safe signals every prespecified time
interval.
[0006] In an embodiment, the processor is further configured to
present to a user an option to override, for a given time duration,
the automatic disabling of the delivery of the irrigation
fluid.
[0007] In another embodiment, the bubble detector is electrically
wired to power leads of the irrigation pump, and is thus configured
to start the detection in response to the irrigation pump being
turned on.
[0008] In some embodiments, the bubble detector is wired in
parallel to an auxiliary power source that retains the bubble
detector in a ready mode, so as to start operating within a given
time delay after the irrigation pump is turned on.
[0009] In some embodiments, the bubble detector is wired in
parallel to an auxiliary power source that powers the bubble
detector regardless of whether the irrigation pump is turned on or
off.
[0010] In an embodiment, the system further includes a drip
detector, which is attached to a drip chamber of a saline bag that
contains saline for use during purge. The drip detector is
configured to send to the irrigation pump an indication that saline
is dripping out of the bag, and if no indication is sent, a pump
logic is configured to disable a purge button.
[0011] In another embodiment, the pump logic is further configured,
if no indication is sent from the drip detector, and an indication
of decreasing level of saline in the drip chamber is received from
a level indicator attached to a drip chamber, to terminate any
ablation currently occurring and reduce the flow rate to an idle
flow.
[0012] There is additionally provided, in accordance with an
embodiment of the present invention, a method including inserting a
probe into a lumen of a patient, wherein the probe is coupled to an
irrigation pump. Delivery of irrigation fluid to the probe is
controlled by turning on and controlling the irrigation pump. In
response to the irrigation pump being turned on, a bubble detector
coupled to a proximal portion of the probe is controlled to
automatically start detection of gas bubbles in the irrigated
fluid, and to transmit fail-safe signals indicating fail-safe
bubble detection is operational. The fail-safe signals are
monitored and, in absence of fail-safe signals, delivery of the
irrigation fluid is automatically disabled.
[0013] The present disclosure will be more fully understood from
the following detailed description of the embodiments thereof,
taken together with the drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic illustration of a catheter-based
cardiac ablation system, according to an embodiment of the present
invention;
[0015] FIG. 2 is a schematic, pictorial illustration of a bubble
detector coupled to a proximal end of a catheter handle, according
to an embodiment of the present invention;
[0016] FIG. 3 is a block diagram that schematically describes a
fail-safe architecture used during the ablation procedure described
by FIG. 1, according to an embodiment of the present invention;
and
[0017] FIG. 4 is a flow chart of steps of an algorithm performed
during the procedure described in FIG. 1 and with the fail-safe
architecture described in FIG. 3, according to an embodiment of the
present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
Overview
[0018] There are a number of invasive procedures, such as an
ablation procedure of an internal organ, where tissue undergoing
the procedure is irrigated. In some cases, bubbles may be created
in the irrigation fluid, which, if reaching the patient undergoing
the procedure, may cause safety issues. Mechanisms for detecting
bubbles at an irrigation pump used to pump the irrigation fluid
may, as described below, fail to operate to detect the bubbles.
[0019] Embodiments of the present invention that are described
hereinafter provide fail-safe bubble detection systems comprising a
bubble detector located at a proximal portion of a probe, such as a
catheter, for insertion into a lumen of a patient. In the disclosed
embodiment, "a proximal portion" means a portion of the probe which
is outside the body of the patient. The probe is connected to a
console that includes a processor-controlled irrigation pump for
delivering irrigation fluid via the probe to irrigate tissue. The
bubble detector has a fail-safe mechanism to ensure that the
detector starts to detect possible gas bubbles in the streamed
fluid in response to the irrigation pump being turned on.
[0020] In some embodiments, a fail-safe wiring architecture is
provided, in which the bubble detector is connected to the
irrigation pump in a way such that, whenever the irrigation pump
starts operating, the bubble detector automatically starts its
operation as well. For example, the bubble detector may be wired to
power leads located on the irrigation pump.
[0021] In some embodiments, the bubble detector periodically
transmits fail-safe signals while operating that indicate proper
operation of the bubble detection system. The processor receives
these fail-safe signals, and, in the absence of the fail-safe
signals, is configured to turn off the irrigation pump and alert a
user that irrigation is disabled. Alternatively, the processor
first alerts the user, and only subsequently, within a prespecified
duration, turns off the irrigation pump.
[0022] In some embodiments, the processor is further configured to
present to the user an option to override the automatic disabling
of irrigation for a given time duration and allow the irrigation
pump to continue operation before being automatically turned off.
In an embodiment, the given duration may be further extended by the
user.
[0023] In some embodiments, a disclosed system for bubble detection
is provided as an add-on to legacy systems, to overcome potentially
hazardous medical scenarios in which irrigation is not sufficiently
monitored for bubbles despite the system being equipped with a gas
bubble detection sub-system.
[0024] By locating an additional bubble detector with fail-safe
mechanisms at a proximal portion of a probe, embodiments of the
present invention may enhance patient safety during an invasive
medical procedure that requires irrigation.
Bubble Detector on Proximal End of Catheter with Fail-Safe
Mechanism
[0025] FIG. 1 is a schematic illustration of a catheter-based
cardiac ablation system 12, according to an embodiment of the
present invention. System 12 is used by a physician 14 to perform
an invasive procedure, which, by way of example, is assumed to
comprise radiofrequency (RF) ablation of a portion of a myocardium
16 of the heart of a patient 18.
[0026] In order to perform the ablation, physician 14 uses a
catheter handle 19 to insert a catheter 20 into a sheath 21 that
has been pre-positioned in a lumen of the patient. Sheath 21 is
positioned so that a distal end 22 of the catheter may enter the
heart of the patient, after exiting a distal end of the sheath, and
then contact tissue of the heart.
[0027] System 12 is controlled by a system processor 46 and
interface circuitry 45. The processor can be programmed to perform
at least one algorithm disclosed herein, the algorithm comprising
steps described hereinbelow. The processor uses interface circuitry
45 in order to perform the algorithm.
[0028] Processor 46 is located in an operating console 48 of system
12. Console 48 comprises controls 49 which are used by physician 14
to communicate with processor 46, which communicates with modules
in a module bank 50 to implement the procedure. The functions of
modules in bank 50 are described below.
[0029] During the procedure performed by physician 14, distal end
22 is supplied with irrigation fluid, typically heparinized normal
saline solution, pumped by an irrigation pump 24. In some
embodiments irrigation pump 24 comprises a peristaltic pump;
alternatively, any other suitable irrigation fluid pump may be
used.
[0030] An irrigation module 56 of processor 46 controls the rate of
flow of the fluid from pump 24 to catheter 20 via irrigation tubing
26. Irrigation module 56, under overall control of processor 46, is
typically configured to vary, as needed, the rate of fluid flow
from a zero rate up to a predefined maximum rate. In one
embodiment, once distal end 22 has been inserted into sheath 21,
module 56 operates pump 24 to provide a minimal fluid flow rate of
approximately 5 ml/min, which is increased by the module when
physician 14 begins ablation.
[0031] Irrigation pump 24 further comprises a bubble detection
sub-system 27, which operates while irrigation fluid is being
provided to the catheter. Bubble detection sub-system 27 is
disposed proximate an outlet of irrigation pump 24. If a bubble is
detected by sub-system 27, the flow of irrigation fluid is
typically halted automatically by processor 46. In some cases,
however, processor 46 initially raises an alarm to physician 14
regarding the presence of bubbles in the irrigation fluid. The
alarm may be an auditory non-verbal warning, such as a ring, or a
recorded statement that is broadcast to the physician.
Alternatively or additionally, the alarm may be a visual warning,
such as a light that is switched on, or a warning notice 62 on
screen 60.
[0032] Bubble detection sub-system 27 is normally disabled
automatically during a "purge" phase (also termed a "splash") that
is used to clear the irrigation tubes. The purge phase is usually
not invoked while catheter 20 is inserted into a patient, however,
such an event may occur accidentally. In this case, bubble
detection sub-system 27 may have no way of detecting if a bubble
enters the patient, with consequent problems.
[0033] Embodiments of the present invention provide an extra bubble
detector 25 to protect against events of irrigation operating with
bubbles that are not prevented by detection sub-system 27. Bubble
detector 25 is connected to irrigation pump 24 via a cable 37, in a
fail-safe scheme ensuring that whenever irrigation pump 24 is
turned on, bubble detector 25 automatically starts operation to
detect bubbles. However, in order to enable purge, in one
embodiment, bubble detector 25 turns off when the physician pushes
a dedicated purge button for initiating a purge. In another
embodiment, bubble detector 25 is disconnected from the proximal
portion of the catheter whenever a purge (e.g., a splash) is done,
and only afterwards the physician connects bubble detector 25 to
the catheter.
[0034] For example, a fail-safe scheme may be realized by bubble
detector 25 being wired directly to the power leads of irrigation
pump 24. In some embodiments, bubble detector 25 may be connected
to irrigation pump 24 via a cable. In other embodiments, a logic is
used for the fail-safe scheme, with bubble detector 25 connected
wirelessly to a control of irrigation pump 24, to trigger the
disabling of pump 24.
[0035] In an optional embodiment, a drip detector or a level
indicator is attached to a drip chamber of a saline bag that
contains saline for use during purge. The drip detector sends to
the irrigation pump an indication that saline is flowing out of the
bag. If no indication is sent (as there is no saline flowing out of
the bag) then a pump logic is configured to disable a purge button,
described below, as the bag is empty.
[0036] In an optional embodiment, the pump logic may be configured
to identify when there are no drops, but the level indicator is
decreasing (indicating that the saline is flowing but the bag is
empty). In this scenario, the pump logic can terminate any ablation
currently occurring and reduce the flow rate to idle flow. This can
allow the physician sufficient time to replace the empty IV bag
before air is drawn into the tubing and the irrigation is forced to
stop. The combination of both a drop counter and a level indicator
can also allow for identification of occlusion, whether from a
closed stopcock or an occluded device.
[0037] Bubble detector 25 is located (e.g., incorporated into or
fitted over) a proximal portion of catheter 20 and is configured to
transmit signals to processor 46 via a cable 35 in response to
bubbles detected in the irrigation fluid. The processor is
configured to halt the irrigation flow if the extra bubble detector
detects a bubble. Thus, even if bubble detection sub-system 27 of
irrigation pump 24 is disabled, irrigation can be disabled when
bubbles are detected.
[0038] In some embodiments, bubble detector 25 is an add-on to
legacy probes, for example by fitting the detector on an irrigation
tube of catheter 20 and electrically connecting bubble detector 25
to console 48 to perform the steps described in FIG. 4. At the same
time, processor 46, or another controller of irrigation pump 24, is
configured to perform steps responsively to signals from bubble
detector 25, as also described below in FIG. 4.
[0039] In some embodiments, bubble detector 25 functions in a
fail-safe mode to ensure that irrigation is disabled unless bubble
sensor 25 actively indicates that it is operating. In an
embodiment, bubble detector 25 is configured to transmit a
fail-safe signal to processor 46 via a cable 35 to indicate that
bubble detector 25 is active at a prespecified time interval (e.g.,
periodically). Processor 46 in configured to turn off irrigation
pump 24 unless such a fail-safe signal is received within a
prespecified duration. The prespecified duration and time-interval
are adjustable. In another embodiment, the processor alerts
physician 14, using one of the methods described above, before
disabling irrigation.
[0040] In another embodiment, bubble detector 25 includes a
self-test, such as exist in the industry, to detect failure of
detector 25, whereby bubble detector 25 is configured to stop
sending the fail-safe signals via cable 35 in case such failure is
self-detected.
[0041] Processor 46 uses a temperature module 52 to analyze signals
received from temperature sensors in distal end 22. From the
analyzed signals, processor 46 determines temperatures of the
distal end, and, in an embodiment, uses the sensed temperatures in
a bubble-detection algorithm described in the aforementioned U.S.
Patent Application Publication 2019/054256 filed Aug. 15, 2017,
entitled "Detection of Bubbles in Irrigation Fluid," which is
assigned to the assignee of the present patent application and
whose disclosure is incorporated herein by reference.
[0042] Module bank 50 also comprises an ablation module 54, which
enables processor 46 to inject RF current via selected electrodes
of distal end 22 (described below), and returning electrodes on the
skin of the patient (not shown in the diagram), into myocardium 16,
in order to ablate regions of the myocardium which are in contact
with the selected electrodes. The ablation module also enables the
processor to set parameters of the injected current, such as its
frequency, the power dissipated, and the duration of the
injection.
[0043] In order to operate system 12, module bank 50 typically
comprises modules other than those described above, such as a force
module enabling the processor to measure a force on the distal end,
and an electrocardiogram (ECG) module enabling the processor to
acquire electro-potentials from myocardium 16 via electrodes in the
distal end. For simplicity, other such modules are not illustrated
in FIG. 1. All modules may comprise hardware as well as software
elements.
[0044] The software for processor 46 and the modules of module bank
50 may be downloaded to the processor in electronic form, over a
network, for example. Alternatively or additionally, the software
may be provided on non-transitory tangible media, such as optical,
magnetic, or electronic storage media. The processor, and typically
the modules, comprise memory used to store the downloaded software,
as well as to store data generated by system 12.
[0045] Processor 46 may present results of the procedure performed
by physician 14, as well as results of the algorithm described
below with reference to FIG. 4, on a display screen 60.
Fail-Safe Bubble Detection
[0046] FIG. 2 is a schematic, pictorial illustration of a bubble
detector 125 coupled to a proximal end of a catheter handle 19,
according to an embodiment of the present invention. In this
embodiment, physician 14 can readily disconnect bubble detector 125
from the proximal portion of the catheter whenever a purge (e.g., a
splash) is done, and only afterwards physician 14 reconnects bubble
detector 125 to handle 19 to provide the disclosed fail-safe
configuration.
[0047] FIG. 3 is a block diagram that schematically describes a
fail-safe architecture 66 used during the ablation procedure
described by FIG. 1, according to an embodiment of the present
invention. As seen, pump 24 is connected to an electromotive power
source 59. Processor 46 can instruct, via a line 55, a relay device
57 to close or open a switch 47, and thereby switch pump 24 on and
off, respectively. In FIG. 3, bubble detector 25 is wired parallel
to pump 24 in a fail-safe power wiring scheme, where the detector
is wired to power leads 44a and 44b of the irrigation pump. This
fail-safe power wiring scheme ensures that bubble detector 25 is
switched on whenever pump 24 receives operating power.
[0048] While operating, bubble detector 25 sends fail-safe signals
to processor 46 via line 35, for processor 46 to regularly verify
that bubble detector 25 is properly operating. If processor 46
stops receiving the fail-safe signals, processor 46 directs relay
57, via a command line 55, to open switch 47 so as to turn off
irrigation pump 24 and stop the flow of irrigation fluid. Examples
of fail-safe signals are signals that give an effective temperature
in the vicinity of bubble-detector 25 via a temperature sensor that
works only if bubble detector 25 is active.
[0049] In an optional embodiment, bubble detector 25 is wired in
parallel to another power source (not shown) that enables the
bubble detector to be in a ready mode, so as to start operating
within a given time delay after the irrigation pump is turned on.
In another optional embodiment, the other power source enables the
bubble detector to operate regardless whether the irrigation pump
is turned on or turned off.
[0050] The example of the fail-safe architecture 66 shown in FIG. 3
was chosen purely for the sake of conceptual clarity. In practice,
a fail-safe mechanism may be devised differently, or include
additional elements (e.g., an uninterruptible power supply (UPS)),
as would occur to a person having ordinary skills in the art.
[0051] FIG. 4 is a flow chart of steps of an algorithm performed
during the procedure described in FIG. 1 and with the fail-safe
architecture 66 described in FIG. 3, according to an embodiment of
the present invention.
[0052] The algorithm, according to the presented embodiment,
carries out a process that begins with physician 14 first
activating irrigation, including turning on pump 24, purging the
irrigation channel and establish idle flow rate, in a turning on
irrigation step 70. Next, physician 14 inserts catheter 20, which
is plugged into console 48 and coupled to irrigation pump 24, into
a sheath 21 that has been pre-positioned in a lumen of patient 18,
at a catheter insertion step 72.
[0053] By being wired to irrigation pump 24 according to fail-safe
architecture 66 and, bubble detector 25, which is located at a
proximal portion of catheter 20, is automatically turned on and
commences bubble detection, at a bubble detection step 74. However,
in order to enable step 70, in one embodiment, bubble detector 25
turns off when the physician pushes a dedicated button for
initiating a purge.
[0054] Bubble detector 25 transmits fail-safe signals to indicate
that the detector is properly carrying out bubble detection, at a
fail-safe signaling step 76.
[0055] The fail-safe signals are received, at a receiving fail-safe
signals step 78, by processor 46 that controls irrigation module
24.
[0056] Processor 46 continuously checks that the fail-safe signals
are received, as required, during every prespecified time interval,
in a fail-safe checking step 80. As long as the fail-safe signals
are received the process returns to step 78 to continue monitoring.
If processor 46 does not receive fail-safe signals within the
prespecified duration, processor 46 then instructs turning off
irrigation pump 24, at a fail-safe turning off step 82. At the same
time, processor 46 issues an alert to the user, e.g., by the
audiovisual methods described above, that irrigation is being
turned off, at an alerting step 84.
[0057] Although the embodiments described herein mainly address
cardiac applications, the methods and systems described herein can
also be used in other clinical applications, such as in any
invasive medical procedures that require flowing liquid into a body
of a patient during procedure.
[0058] It will be appreciated that the embodiments described above
are cited by way of example, and that the present invention is not
limited to what has been particularly shown and described
hereinabove. Rather, the scope of the present invention includes
both combinations and sub-combinations of the various features
described hereinabove, as well as variations and modifications
thereof which would occur to persons skilled in the art upon
reading the foregoing description and which are not disclosed in
the prior art.
* * * * *